The North West Counter Terrorism Unit (NWCTU) said the teenager was held on Saturday on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism.

He was first arrested on April 2 but then detained again after officers examined "devices" and allegedly uncovered communications with a man in Australia.

Head of the NWCTU, Detective Chief Superintendant Tony Mole, said: "We seized some media devices and we found some communications on those devices that were a concern to us.

"We thought it indicated a potential credible terrorist attack in Australia. We immediately contacted the Australian authorities and we've been working with them since in relation to the material that we uncovered.

"As a result, I think it's been widely reported in the media the action that's been taken in Australia in relation to the arrests, house searches and some charges."

Mr Mole said the teenager remains in custody and his team will liaise with the Crown Prosecution Service to decide how to proceed.

Asked if the information his officers uncovered led directly to the Australian anti-terror operation, he said: "I think what's fair to say is that we've provided some highly significant information in evidence to the Australian authorities that's resulted in this action."

Counter-terrorism officers executed a warrant at an address in Blackburn on April 2, and the teenager was arrested on suspicion of preparing for an act of terrorism.

Mr Mole said he could not give further details about the first arrest.

The senior officer stressed there is no indication of any imminent threat in the UK.

Mr Mole said: "We are continuing to work closely with the police in Australia and Lancashire and I want to reassure the public that we have not uncovered an imminent attack in the UK and there is no immediate threat towards the communities of Lancashire, the North West and the UK.

"It is important to remind communities and families to bring to our attention anyone they perceive may be vulnerable or in danger of escalating towards terrorism.

"We have the ability to engage and support individuals where necessary."

In a joint statement, Victoria Police and the Australian Federal Police said they "can confirm a link between the arrest of a 14-year-old boy in Blackburn, Lancashire, in the United Kingdom on Saturday with Operation Rising, a Joint Counter Terrorism Team operation".

It said: "Investigators received information from UK authorities after they allegedly uncovered communications between the teenager and a man in Australia.

"The nature of the communication will form part of the investigation and therefore it would not be appropriate to comment further."

Counter-terrorism officers in Australia arrested two teenagers on Saturday on suspicion of planning an attack at an Anzac Day ceremony in Melbourne later this month. The plot is alleged to have involved targeting police officers.

The annual Anzac Day ceremonies - commemorating the Australian and New Zealand Army Corps' First World War battle in Gallipoli on April 25 - take on extra significance this year as the centenary of the conflict in Turkey is marked.

The Australian police operation saw five men arrested, including an 18-year-old who has appeared before magistrates charged with conspiracy to commit acts done in preparation for, or planning, terrorist acts.

Two men, aged 18 and 19, have been released pending further inquiries, while another 18-year-old has been released but police expect him to be charged with weapons offences. A further 18-year-old remains in custody.

Over the weekend British police disclosed that security operations for Anzac-related events in the UK are being reviewed following the developments in Australia.

After the arrest in Blackburn, Scotland Yard said: "There is no change to the security announcement made on Saturday about asking forces to review plans for Anzac Day-related events to ensure they are safe and secure for visitors and officers."

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